Twitter is banning ads from RT and Sputnik International, two media groups that US intelligence claims helped the Russian government spread propaganda during last year's presidential election.
Twitter based its decision on US intelligence findings, and the company's own internal investigation, it said in a Thursday blog post.
"We did not come to this decision lightly, and are taking this step now as part of our ongoing commitment to help protect the integrity of the user experience on Twitter," the company said.
In a January report, US intelligence claimed that both RT, formerly known as Russia Today, and Sputnik were part of a state-run "propaganda machine" from the Kremlin.
That propaganda machine published "consistently negative" coverage of presidential candidate Hillary Clinton during last year's election, including accusing her of corruption, poor health, and ties to Islamic extremism, according to the U.S. intelligence findings.
On Thursday, Twitter said its decision was effective immediately. However, "RT and Sputnik may remain organic users on our platform, in accordance with the Twitter Rules," the company added.
Twitter announced the advertising ban as the company faces scrutiny over Russia's suspected efforts to exploit social media to influence US public sentiment. US lawmakers are worried the company is doing too little to stop the problem.
However, both RT and Sputnik were quick to denounce Twitter's decision.
"This is highly regrettable," said Margarita Simonyan, the editor-in-chief for both media groups. She went on to suggest that the Kremlin will retaliate, by cracking down on US media in Russia.
Hope @jack won't forget to tell @congressdotgov how @Twitter pitched @RT_com to spend big $$s on US elex ad campaign. pic.twitter.com/7GqoEoSaY8 — ????????? ???????? (@M_Simonyan) October 26, 2017
RT also published a lengthy article claiming that it never violated Twitter's advertising rules. Instead, the social media company had sought to strike more advertising deals with the Russian media agency.
"RT has never spread any sort of deliberate misinformation," it added.
Twitter said it's earned $1.9 million from RT since the media group began advertising on the platform in 2011. However, the company also stated it will "donate" that money to external research on how Twitter can be used in civic engagement and elections.